Lecture
16:
Emotions
and
Limbic
System
Limbic
System
• Closest
connection
with
olfactory
system
and
hypothalamus
• Oldest
areas
of
telencephalon,
bordering
diencephalon.
Limbic
means
"border".
• telencephalon:
olfactory
processing,
sex
and
emotional
behavior
• Starts
at
non
cortical
area
to
cortical
olfactory
areas
and
cortical
limbic
areas
• Limbic
=
border
à
areas
that
border
the
diencephalon,
underneath
the
cerebral
cortex
• Important
in
human
mental
diseases
• Unlike
cerebral
cortex,
limbic
system
has
DIRECT
connections
with
olfactory
and
taste
systems,
hypothalamus
(visceral
&
emotional).
• Strong
connection
with
dopamine
system
(motivation
of
behavior)
• Areas
bordering
the
diencephalon
• Has
direct
connections
with
visceral
systems
(olfac tory
and
taste)
and
direct
connection
with
hypothalamus
(visceral
integration
system)
• Limbic
system
areas
can
be
grouped
into
2
categories:
• Transition
from
subcortex
(e.g.
amygdala)
to
3 -‐4
layered
cortex
(e.g.
hippocampus)
to
6-‐layered
neocortex.
1) oldest
areas:
subcortical
areas
(closely
connected
with
the
hypothalamus
and
amygdala),
includes
amygdala
nuclei,
nuclei
accumbens
(Reward
behaviors)
ventral
pallidum,
BNST
–
non
cortical
deep
limbic
system
structures
2) cortical
structures:
amygdala
(at
the
anterior
tip
of
the
hippocampus),
deep
temporal
lobe
structures,
olfactory
bulb
(connects
with
amygdala
and
entorhinal
cortex),
hippocampal
area
continues
connections
with
the
Cingular
gyrus
and
forebrain
(to
frontal
cortex
–
basal
forebrain
nuclei,
limbic
frontal
cortex
structures)
• Interconnections:
"Papez
Circuit"
Subcortical
Limbic
Systems
(Extended
Amygdala)
-‐
interconnected
• Amygdala
• Emotion
and
emotional
learning
• Basal
Forebrain
Nuclei
(Ch1 -‐4)
• Bed
Nucleus
of
Stria
Terminalis
• Sex
and
gender
• Ventral
Pallidum
• Pair
boding
with
vasopressin
next
to
nucleus
accumbens
• Septum
• Nucleus
Accumbens
(Ventral
Striatum)
• Important
in
emotional
behaviours
• Olfactory
Tubercle
o These
are
closely
collected
subcortical
structures
o Heimer:
all
of
these
structures
can
be
identified
becau se
they
all
have
direct
connections
to
amygdala
(major
output
for
emotional
behaviours)
–
extended
amygdala
• Can
be
associated
with
the
olfactory
system
–
rhinecephalon
• Rhinecephalon
emphasizes
that
these
structures
also
have
connections
with
olfactory
syst em
o These
are
the
oldest,
most
primitive
areas
of
the
forebrain
Cortical
Limbic
Systems
(higher
limbic
systems)
• Hippocampus
• hippocampus:
highly
structured
and
highly
layered
–
important
for
emotional
learning
à
declarative
memories
and
cognitive
learning
• from
emotional
system
to
high
cognitive
processing
system
for
memory
• Connected
with
hippocampus
–
closely
connected
temporal
lobe
structure:
subiculum
and
parahippocampal
areas
à
extend
right
out
of
hippocampus
• Subiculum
• Entorhinal
Cortex
• olfactory
processing
and
spatial
maps
• Cingulate
Cortex
• Extends
upward
from
hippocampus,
up
to
parietal
lobe,
above
the
corpus
collosum
• Insular
Cortex
• Orbitofrontal
Cortex
• (Dorsolateral
Frontal
Cortex)
o As
these
structures
grow,
they
pull
underlying
into
c
shape
structure
• Temporal
pole
à
cingular
gyrus
à
orbital
frontal
cortex
(most
anterior
tip
of
the
C)
• Temporal
lobe
structures
à
parietal
lobe
structures
à
frontal
lobe
structures
as
we
follow
the
C
o C
shape
structure:
all
brain
structure
form
layers
in
C
shape
structure
Limbic
system
and
Emotion
-‐ just
above
the
eyeball,
the
orbital
frontal
cortex
–
limbic
frontal
cortex
just
in
front
of
basal
forebrain
o important
in
emotional
processing
-‐ just
above
this,
anterior
cingulate
cortex ,
important
in
depression
and
emotional
processing
-‐ behind
that
is
the
posterior
circulate,
continues
into
temporal
lobe
-‐ 2
areas
of
temporal
lobe
that
are
important
à
amygdala
and
just
above
it
is
the
sylvian
fissure
(divides
temporal
and
parietal
lobe)
o inside
the
Sylvian
Fissure
is
the
Insular
Cortex
–
visceral
cortex
important
for
taste
processing
and
olfactory
decision
making
à
makes
emotional
decisions
Early
Studies
• Temporal
lobe
lesions
(Klüver -‐Bucy
Syndrome)
lead
to
tame
monkeys,
fearless
and
hypersexual.
• Seizures
associated
with
temporal
lobe
• Temporal
lobe
epilepsy
leads
to
emotional
auras
and
behaviors.
• Tumors
or
scar
tissue
in
temporal
lobe:
strange
emotional
auras
followed
by
loss
of
consciousness
(Feelings
of
panic
and
anger)
• Temporal
lobe
removed?
Strange
behaviors
of
fearlessness
(monkeys
lose
understanding
of
social
hierarchy)
–
less
fearful
of
humans
à
become
tamed
in
presence
of
humans
• Strange
social
responses
and
hypersexual
(mount
poles)
• Social
relationships
and
emotional
behavior
dependent
on
temporal
lobe?
•
Stimulation
of
amygdala
lea ds
to
attack,
rage
or
positive
affect.
• Electrically
stimulate
amygdala:
produce
same
feelings
in
temporal
lobe
epilepsy
• Local
stimulation
of
amygdala:
sexual
feelings,
rage,
attack
–
very
intense
emotional
feelings
without
awareness
of
circumstances
• amygdala
important
in
violent
behavior?
No.
But
activation
of
it
will
produce
violence
• important
for
uncontrollable,
undefined
emotional
response
behaviors
• Stimulation
of
hippocampal
region
leads
to
experiential
reports
"deja
vu".
(Penfield)
• Deep
personal
feelings
à
personal
events
in
early
life
à
déjà
vu
reports
• Especially
in
left
temporal
lobe
à
reports:
delusional
reports
of
something
in
the
past
(Feel
as
if
they
are
transported
back)
Conditioned
Fear
Paradine
• Tone
(Conditioned
stimulus)
• In
rodents,
discovered
amygdala
is
important
for
learned
(Conditioned)
fear
• Involves
discrete
pathways
that
go
to
amygdala
that
induce
defensive
responses
in
brain
stem
• Neutral
stimuli
and
fearful
stimuli
occurs
in
lateral
nucleus
of
amygdala
• Conditioned
stimuli
(tone)
presented
alone
and
produces
small
response
• This
is
then
paired
with
an
unconditioned
stimulus
(usually
weak
shock)
• Shock
(Unconditioned
stimulus)
• Unconditioned
stimuli
produces
uncomfortable
response
in
animal
• Fear
Responses:
Increased
heart
rate,
Increas
More
Less
